Setup fuzzer for parser

flake.nix

@@ -44,5 +44,13 @@
             export NIL_PATH="$(cargo metadata --format-version=1 | jq -r .target_directory)/release/nil"
           '';
         };
+
+        devShells.fuzz = pkgs.mkShell {
+          packages = [
+            rustPkgs.rust-nightly_2022-08-01
+            pkgs.cargo-fuzz
+          ];
+          RUST_BACKTRACE = 1;
+        };
       });
 }

syntax/fuzz/.gitignore

@@ -0,0 +1,4 @@
+target
+corpus
+artifacts
+Cargo.lock

syntax/fuzz/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "syntax-fuzz"
+version = "0.0.0"
+authors = ["Automatically generated"]
+publish = false
+edition = "2018"
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+libfuzzer-sys = "0.4"
+
+[dependencies.syntax]
+path = ".."
+
+# Prevent this from interfering with workspaces
+[workspace]
+members = ["."]
+
+[[bin]]
+name = "parser"
+path = "fuzz_targets/parser.rs"
+test = false
+doc = false

syntax/fuzz/fuzz_targets/parser.rs

@@ -0,0 +1,6 @@
+#![no_main]
+use libfuzzer_sys::fuzz_target;
+
+fuzz_target!(|text: &str| {
+    syntax::parse_file(text);
+});